<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>排他思想(算法)</title>
    <style>
      button {
        cursor: pointer;
      }
    </style>
  </head>
  <body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
    <button>按钮5</button>

    <script>
      var btns = document.getElementsByTagName('button');

      for (var i = 0; i < btns.length; i++) {
        btns[i].onclick = function () {
          // 1、先清除所有元素的样式
          for (var j = 0; j < btns.length; j++) {
            btns[j].style.backgroundColor = '';
          }

          // 2、设置当前元素的样式
          this.style.backgroundColor = 'pink';
        };
      }
    </script>
  </body>
</html>
